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, WLH. GATES.

TRAMMEL.

No. 522,053. Patented June 26, 1894.

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WILLIAM H.

PATENT OFFI E.

GATES, OF WORCESTER, MASSACHUSETTS, ASSIGNOR OF ONE- I-IALF TO ERNEST F. DAKIN, OF SAME PLACE.

TRAMMELQ SPECIFICATION: forming part of Letters Patent No. 522,053, dated June 26, 1894.

Application fil d October 2, 1893.

To all whom, it may concern:

Be it known that L'WILLIAM I-I. GATES, a citizen of the United States, residing at Worcester, in the county of Worcester and State of Massachusetts, have invented certain new and useful Improvements in Trammels; and I do hereby declare that the following is a full, clear, and exact description thereof, Which,in connection with the drawings making a part of this specification, will enable others skilled in the art to-which my invention belongs to make and use the same.

My invention relates to trammels, and more particularly to'that class of trammels or beam calipers, in which two heads or slides carrying a pencil or point, are supported, and adapted to be moved relatively to each other, on a beam or bar, in parallel planes, and the object of my invention is to improve upon the construction of trammels of the class above referred to, and to provide a trammel having a metal beam or bar, in which a very fine adjustment of one of the heads or slides carrying a point, relatively to the other head or slide, may be obtained, and in which the point or pencil is combined with the slide or head in such a way, that the same may be readily removed, and another substituted.

My invention consists in certain novel features of construction and operation of a trammel, as will be hereinafter fully described.

Referring to the drawings :Figure 1 is a side elevation of a trammel, embodying my improvements, and Fig. 2, is, on an enlarged scale, a central vertical section of the right hand end of the trammel shown in Fig. 1.

In the accompanying drawings, 1 is the trammel beam or bar, which in this instance consists of a round metal rod flattened on its top surface 1', to prevent the trammel heads or slides from turning round, when moved horizontally thereon. The bar 1 may be of any other material, if desired, and may be of any desired shape in cross section, as square, one.

The two trammel heads or slides 2, carrying the trammel points 3, and mounted to slide horizontally on the bar 1, are of similar construction, and in this instance are made post shaped with the upper end preferably knurled, and extending above the bar 1, and the lower end, carrying the trammel point 3,

Serial No. 486,972. ltNo model.)

extending below the bar 1. The middle portion 2' is preferably enlarged, and bored through, to receive the bar 1. I

Each trammel head or slide 2 is secured to the bar 1, after it has been horizontally adjusted thereon, by a thumb nut 4, turning on a thread cut on the slide 2 above the central portion 2 thereof, and bearing against a Washer 5, loosely mounted on the slide 2, and resting on the flattened portion 1' of the bar 1, see Fig. 2, thus binding the bar 1 in the hole in the slide 2.

i The point 3 is removable, and is preferably of the form and construction shown in Fig.2, with the upper portion 3 which extends into the vertical hole 6 in the lower end of the slide 2, of larger diameter than the lower portion, and with the upper end of said point bearing against the inner end of said hole 6'. The upper portion 3 of the point 3, of enlarged diameter, extends a little below the lower end of the slide 2, and by reducing the diameter of the lower portion of the point 3, a shoulder 3' is formed on the point, and this shoulder extends below the lower end of the slide 2, and does not come in contact with the lower end of said slide, and is engaged by the internal shoulder 8' on the binding nut or screw cap 8, screwed onto the external screw thread 7 on the lower end of the slide 2, to retain the point 3 in the slide 2, with the inner end of said point bearing against the inner end of the hole 6 in said slide.

By securing the point 3 to the slide 2, in the manner above described, it can be readily removed in case it breaks, or for any other reason, and another point substituted; and the vertical center of the point, relatively to the verticalcenter of the supporting slide or head, is always maintained, and the vertical centers of the two points, relatively to each other, are always maintained in planes parallel to each other, so as to always obtain a true parallelism of the two points.

I will now describe my adjusting mechanism combined with the trammel bar '1, for obtaining a very fine and accurate adjustment of one of the trammel points;said mechanism is shown at the right in Fig. 1, and also in Fig. 2. v

A collar 9, is secured upon the bar 1, near too one end thereof, in this instance by a pin 10. A spiral spring 11 loosely encircles the bar 1, and has its hearing at one end against the collar 9, and at its otherend against a collar 12, loosely supported on the bar 1; the collar 12 is interposed between the middle portion 2' of the slide 2, and the spiral spring 11. Upon the opposite side of the slide 2, from the collar 12, is loosely supported on the bar 1, a second collar 13. A thumb nut 14, which is supported and turns on the turned down screw threaded end 1" of the bar 1, bears against the outer end of said collar 13. The thumb nut 14 may be provided with a graduated scale, as shown in Fig. 1, if desired.

The operation of my adjusting mechanism will be readily understood by those skilled in the art, from the above description in connection with the drawings, and is as follows:

The approximate adjustment of one trammel point 3, to the position desired, is obtained by loosening the thumb nut 4, and moving the slide 2 at the left in Fig. 1, horizontally in either direction on the bar 1, and then tightening said thumb nut, to secure the slide 2 in its adjusted position on the bar 1. The accurate and fine adjustment of the other trammel point is now obtained by means of my adjusting mechanism, shown at the right in Fig. 1. The thumb nut 4 is loosened enough to allow the slide 2 at the right in Fig. 1, to move horizontally on the bar 1, and then said slide 2, carrying the point 3, is moved toward the other slide, against the action of the spring 11, to bring the points 3 nearer together, by turning the thumb nut 14 in one direction on the threaded end 1" of the bar 1, and the slide 2 is moved in the opposite direction, away from the other slide, by turning the thumb nut 14 in the opposite direction, allowing the spring 11 to act to move the slide 2 on the bar 1.

When the accurate adjustment of the trammel point is made, as above described, the thumb nut i is screwed down to bind the slide 2 on the bar 1.

It will be seen, that by means of thethumb nut 14, in connection with the actuating spring 11, a very fine and accurate adjustment of the trammel point, at one end of the trammel bar, can be obtained, without affecting the parallelism of the tram mel points.

The fineness of the thread 1", cut on the end of the bar l,will regulate the movement of the slide 2 to the thousandth part of an inch, if desired.

It will be understood that the details of construction of some of the parts of my trammel maybe ,varied somewhat if desired.

The shape of the trammel heads or slides 2 may be changed if desired, and the trammel points may be attached to the lower ends of the slides 2 in any well known way.

Having thus described my invention, what I claim as new, and desire to secure by Letters Patent, is-- 1. The combination with a trammel bar or beam, flattened on its top surface, and a slide or head carrying a trammel point, supported and horizontally movable on said bar or beam, of means for adjusting said slide or head, consisting of a thumb nut supported and turning on a screw thread, at one end of the trammel bar, and engaginga collar interposed between said slide and nut, and a coil spring supported on the trammel bar, on the opposite side of said slide from said thumb nut, and bearing at one end against a collar secured upon thetrammel bar, and at its other end againsta collar loosely supported on the bar between said spring and slide, substantially as shown and described.

2. The combination with a trammel bar or beam, flattened upon its top surface, and having one end of reduced diameter and screw threaded, and two slides or heads carrying trammel points, supported and adapted to move horizontally on said bar, and means for securing said slides or heads to the bar, consisting of a thumb nut, turning on said slides, a collar loosely mounted on said slides, and engaged by said thumb nut, and held against the flattened surface of the trammel bar or beam, of means for obtaining a fine adjustment of one of said slides upon the trammel bar or beam, consisting of a spiral spring supported on the trammel bar, on the inside of the slide, and adapted to act to move the slide toward the end of the bar, and a thumb nut turning on the screw threaded end of the trammel bar, and adapted to move the slide inward against the action of said spring, substantially as set forth.

3. The combination with a trammel bar or beam, flattened on its top surface, and a slide or head supported and horizontally movable on said bar or beam, said slide or head carrying a removable point adapted to extend into a vertical hole therein, with the inner end of the point bearing against the inner end of said hole, and having its upper portion of larger diameter than its lower portion, to form a shoulder on the point, below the end of the slide, and a binding nut or screw, provided with an internal shoulder to engage the shoulder on the point, and screwed onto the end of the slide, to secure the point there to, of means for obtaining a fine adjustment of the slide upon the trammel bar or beam, consisting of a spiral spring supported on the trammel bar, on the inside of the slide, and adapted to act to move the slide toward the end of the bar, and a thumb nut turning on the screw threaded end of the trammel bar, and adapted to move the slide inward against 1 116 1action of said spring, substantially as set ort WILLIAM II. GATES.

Witnesses:

JOHN C. DEWEY, KATHARINE FARRELL.

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